Cigarette mainstream smoke component adsorbent and cigarette filter

ABSTRACT

The present invention provides a cigarette mainstream smoke component adsorbent including particulate activated carbon, and a glucan film supported by the particulate activated carbon. Also, the present invention provides a cigarette filter including the cigarette mainstream smoke component adsorbent.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a Continuation Application of PCT Application No.PCT/JP2009/054472, filed Mar. 9, 2009, which was published under PCTArticle 21(2) in Japanese.

This application is based upon and claims the benefit of priority fromprior Japanese Patent Application No. 2008-070126, filed Mar. 18, 2008,the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a cigarette mainstream smoke componentadsorbent and a cigarette filter comprising the same.

2. Description of the Related Art

A flavorant is added to leaf tobacco shreds used in a cigarette in orderto adjust the flavor and the taste. The flavorant includes a primaryflavorant as a casing source and a secondary flavorant as a top flavor.The components of the secondary flavorant exhibit relatively highvolatility and are likely to be decomposed by heat. Accordingly, whenthe cigarette containing the secondary flavorant is smoked, the smokerwould taste the flavor to a lesser extent because of the volatilizationof the secondary flavorant during the storage thereof. In addition, withrespect to the cigarette provided with a charcoal (activated carbon)filter which adsorbs cigarette mainstream smoke components, thesecondary flavorant migrates to and is adsorbed on the charcoal,resulting in a partial deterioration of the flavor and taste. Thecharcoal having the secondary flavorant adsorbed thereon suffers adecreased capability of removing tobacco mainstream smoke components.

The specification of Japanese Patent No. 3744953 discloses a tobaccofilter incorporating capsules containing a deodorant, such as activatedcarbon. These capsules are destroyed by external force when stubbing outthe cigarette to thereby release the deodorant within the filter, thuseliminating the smoke odor. However, because in this tobacco filter thedeodorant is encapsulated in the capsules and the capsules are destroyedby external force when stubbing out the cigarette after smoking tothereby release the deodorant within the filter, the deodorant cannotexert its function during smoking the cigarette.

BRIEF SUMMARY OF THE INVENTION

It is an object of the present invention to provide an adsorbent and acigarette filter capable of suppressing the adsorption of a flavorantduring non-smoking and capable of adsorbing cigarette mainstream smokecomponents during smoking.

According to one aspect of the present invention, there is provided acigarette mainstream smoke component adsorbent characterized bycomprising particulate activated carbon and a glucan film supported bythe particulate activated carbon.

According to another aspect of the present invention, there is provideda cigarette filter comprising a cigarette mainstream smoke componentadsorbent according to the present invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 is an enlarged schematic cross-sectional view of a cigarettemainstream smoke component adsorbent according to one embodiment of thepresent invention.

FIG. 2 is an enlarged schematic cross-sectional view of part of acigarette mainstream smoke component adsorbent according to oneembodiment of the present invention.

FIG. 3 is a schematic longitudinal sectional view of a cigarette with afilter according to one embodiment of the present invention.

FIG. 4 is a schematic longitudinal sectional view of a cigarette with afilter according to another embodiment of the present invention.

FIG. 5 is a graph showing the flavorant adsorbing performance of anadsorbent according to the present invention, together with that of acomparative example.

FIG. 6 is a graph showing the flavorant adsorbing performance afterstorage of a cigarette with a filter containing an adsorbent accordingto the present invention, together with that of a comparative example.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be described in greater detail below withappropriate reference to the appended drawings. Like elements areidentified by like numerals throughout all the drawings, and repetitionof detailed descriptions will be avoided.

A cigarette mainstream smoke component adsorbent according to thepresent invention comprises particulate activated carbon and a glucanfilm supported by the particulate activated carbon.

The origin of the activated carbon for use in the present invention isnot particularly limited. Use may be made of a spherical or powderyactivated carbon with fine pores (diameter 10 to 200 Å) obtained byreacting a natural material, such as coal or palm husk, as a rawmaterial with a gas or chemical at a high temperature. Activated carbonparticles whose average particle diameter is 75 to 1000 μm can besuitably employed. The specific surface area of the activated carbon asmeasured in accordance with the BET method is preferably 800 to 2000m²/g, more preferably 1000 to 1200 m²/g.

The glucan film is formed of, for example, pullulan, maltodextrin,hydroxypropylcellulose or the like and is water-soluble. In order tosoften the glucan film, a protein such as gelatin, a gummy saccharidesuch as carrageenan, gellan gum, locast bean gum or gum arabic, amonosaccharide, a sugar alcohol, a cellulose derivative or a polyol suchas glycerol or polyethylene glycol can be contained in the glucan film.Such a film softening agent can be used in an amount of 0.1 to 3% basedon the weight of glucan. Further, the glucan film may contain a colorantother than black colorants in order to conceal the blackness of theactivated carbon and improve the appearance of the adsorbent. Examplesof such colorants are a water-soluble pigment such as an annattopigment, calcium carbonate and the like. The colorant is used in anamount sufficient to cause the glucan to have the same color as that ofthe colorant. For example, the colorant can be used in an amount of 0.1to 1% based on the weight of the glucan.

In one embodiment, the cigarette mainstream smoke component adsorbentaccording to the present invention is free of flavorants (for example,neither the activated carbon particles nor the glucan film contains anyflavorant).

FIG. 1 is an enlarged schematic cross-sectional view of a cigarettemainstream smoke component adsorbent 10 according to one embodiment ofthe present invention. In this adsorbent 10, a glucan film (for example,a pullulan film) 14 directly covers the entire surface of an activatedcarbon particle (carrier) 12.

The thickness of the glucan film 14 is not particularly limited.However, from the viewpoint of the disruption of the glucan film duringsmoking, it is preferred to form the glucan film 14 using glucan in anamount corresponding to 0.1 to 10% of the weight of the finishedadsorbent.

The adsorbent of the type shown in FIG. 1 can be formed from, forexample, an aqueous solution or aqueous dispersion of glucan optionallycontaining the film softening agent and/or colorant. For example,activated carbon particles are placed in a fluidized-bed granulatingdrier, in which while blowing thereinto a hot air heated at, forexample, 80° C. or below, an aqueous solution or aqueous dispersion ofglucan optionally containing the film softening agent and/or colorant iscontinuously or intermittently sprayed onto the surfaces of theactivated carbon particles and dried. Depending on the composition ofthe aqueous solution or aqueous dispersion of glucan, the drying isimmediately followed by cooling. Thus, the glucan film is formed on thesurface of each of the activated carbon particles.

The glucan film 14 does not infiltrate into the secondary or tertiarypores of the activated carbon particle 12 to plug them up. This aspectis illustrated in FIG. 2. As illustrated in FIG. 2, the glucan film 14covers the entire surface of the activated carbon 12 but does notinfiltrate into the secondary or tertiary pores 12 a thereof.

A cigarette filter according to the present invention comprises acigarette mainstream smoke component adsorbent according to the presentinvention.

FIG. 3 is a schematic sectional view of a cigarette with a cigarettefilter (filter-tipped cigarette) 20 according to one embodiment of thepresent invention. The filter-tipped cigarette 20 comprises a cigarette22 comprising a tobacco filler 221, such as tobacco shreds, wrapped witha cigarette paper 222. The cigarette 22 is the same as a conventionalcigarette. A filter 24 is attached to one end of the cigarette 22. Thefilter 24 comprises a filter section 241 containing the adsorbent of thepresent invention, provided in direct contact with the one end of thecigarette 22. A plain filter section 242 may be provided at that end ofthe filter section 241 on the downstream side with respect to thedirection of the flow of mainstream smoke.

The filter section 241 containing the adsorbent comprising for example,cellulose acetate fibers 241 a, in which adsorbent particles AAPaccording to the present invention dispersed therein, wrapped with afilter wrapper paper 241 b, and may be similar to a conventionalcharcoal filter except that the adsorbent of the present invention isused in place of charcoal (activated carbon).

The plain filter section 242 may be formed of, for example, a tow ofcellulose acetate fibers 242 a wrapped with a filter wrapper paper 242b. Substantially no adsorbent capable of adsorbing mainstream smoke gascomponents is contained in the plain filter section 242.

The filter 24 composed of the filter sections 241 and 242 is fitted tothe cigarette 22 by means of a tipping paper 26.

FIG. 4 is a schematic sectional view of a cigarette with a cigarettefilter (filter-tipped cigarette) 30 according to another embodiment ofthe present invention. In this filter-tipped cigarette 30, a filter 32fitted to the cigarette 22 by means of the tipping paper 26 comprises afirst plain filter section 321 directly fitted to one end of thecigarette 22 and a second plain filter section 322 provided spaced apartfrom the first plain filter section 321. These sections are whollywrapped with a filter wrapper paper 36. The first plain filter section321 and second plain filter section 322 may be comprised of, forexample, tows of cellulose acetate fiber 321 a and 322 a, respectively.The space (cavity) 34 between the first plain filter section 321 and thesecond plain filter section 322 is filled with the adsorbent particlesAAP according to the present invention.

In the filter-tipped cigarette of the present invention, the cigarettemainstream smoke component adsorbent according to the present inventionhas its activated carbon covered by a highly airtight glucan film whenthe cigarette is not smoked (for example, during storage), so that theadsorption of flavorant contained in the cigarette, etc. can besuppressed. Accordingly, the total amount of deliverable flavorantcomponents contained in the cigarette is not decreased before smoking,so that the flavor can be delivered at a relatively high proportion intothe mainstream smoke. When the adsorbent is brought into contact withtobacco mainstream smoke generated by, e.g., repeated smoking actions,the glucan film is for the first time partially dissolved and detachedmainly by highly polar components (moisture, etc.) contained in thetobacco mainstream smoke, so that the inherent adsorptive function ofthe activated carbon can be exerted, thereby attaining the adsorption ofgas components contained in the cigarette mainstream smoke.

EXAMPLES

The present invention will be described by way of Examples below.Needless to say, the present invention is not limited by these Examples.

Example 1

A 5% by weight concentration aqueous pullulan dispersion was prepared.Activated carbon of 250 μm average particle diameter (palm huskactivated carbon employed in conventional charcoal filters; specificsurface area: 1000 m²/g), 15 kg, was placed in a tumbling fluidized-bedgranulation drier (Model SFC-15 manufactured by Freund InternationalLtd.). The agitation blade was rotated at about 200 rpm, and hot air of70 to 80° C. was blown into the drier at a flow rate of 1.0 to 2.0m/sec, thereby forming a fluidized bed of the activated carbonparticles. While maintaining the fluidized bed by continuous agitation,the aqueous pullulan dispersion was sprayed thereinto at 130 to 150g/min. Thus, the aqueous pullulan dispersion, 15 kg in total, wassprayed onto the surfaces of the activated carbon particles, and dried.Thereafter, the activated carbon particles were dried by hot air of 50to 70° C. for 3 to 5 minutes, thereby obtaining 14.7 kg of desiredadsorbent. With respect to the obtained adsorbent, the amount ofpullulan applied on the surfaces of the activated carbon wasquantitatively determined to find that the adsorbent had a 4.5% byweight pullulan film.

Example 2

A 5% by weight concentration aqueous pullulan dispersion was prepared.The same palm husk activated carbon as used in Example 1, 5kg, wasplaced in a fluidized-bed granulation drier (Model MGD-05 manufacturedby Okawara Mfg. Co., Ltd.). While rotating the agitation blade at about20 rpm in order to assist the initial fluidization, hot air of 75° C.was blown into the drier at a flow rate of 0.6 m/sec, thereby forming afluidized bed of the activated carbon particles. Intermittent sprayingcomprising spraying the aqueous pullulan dispersion at a rate of 65g/min for one minute and stopping the spraying for three minutes wasrepeated on the fluidized bed. Thus, the aqueous pullulan dispersion, 2kg in total, was sprayed onto the surfaces of the activated carbonparticles, and dried. Immediately thereafter, the temperature of the hotair was lowered to room temperature and the air was blown at a flow rateof 0.4 m/sec to conduct cooling. Thus, a desired adsorbent was obtained.

Example 3

A 10% by weight concentration aqueous hydroxypropylmethylcellulosedispersion was prepared. The same palm husk activated carbon as used inExample 1, 150 g, was placed in a fluidized-bed granulation drier (ModelGB-22 manufactured by Yamato Scientific Co., Ltd.). While rotating theagitation blade at about 20 rpm, hot air of 80° C. was blown into thedrier at a flow rate of 0.6 m/sec, thereby forming a fluidized bed ofthe activated carbon particles. By continuously spraying the aqueoushydroxypropylmethylcellulose dispersion on the fluidized bed, theaqueous hydroxypropylmethylcellulose dispersion, 15 g in total, wasapplied onto the surfaces of the activated carbon particles, and dried.Immediately thereafter, the temperature of the hot air was lowered toroom temperature and the air was blown at a flow rate of 0.4 m/sec toconduct cooling. Thus, a desired adsorbent was obtained.

Example 4

An aqueous glucan dispersion of 5% by weight pullulan concentration, 5%by weight gelatin concentration and 1% by weight carboxymethylcelluloseconcentration was prepared. The same palm husk activated carbon as usedin Example 1, 150 g, was placed in a tumbling fluidized-bed granulator.The rotating perforated plate disposed at the bottom was rotated atabout 300 rpm, and the agitation blade for preventing granulation wasrotated at about 320 rpm. Hot air of 75° C. was blown into thegranulator at a flow rate of 0.6 m/sec, thereby forming a fluidized bedof the activated carbon particles. By continuously spraying the aboveaqueous glucan dispersion held at 50° C. on the fluidized bed, anaqueous glucan dispersion, 15 g in total, was applied onto the surfacesof the activated carbon particles, and dried. Immediately thereafter,the temperature of the hot air was lowered to room temperature, and theair was blown at a flow rate of 0.4 m/sec to thereby conduct cooling.Thus, a desired adsorbent was obtained.

Example 5

An adsorbent-containing cellulose acetate filter was produced using eachof the adsorbents obtained in Examples 1 to 4 in accordance with theroutine procedure for production of charcoal filters. A filter-tippedcigarette shown in FIG. 3 was produced using each of the obtainedfilters. The maximum amount of adsorbent added to theadsorbent-containing filter section 241 was 80 mg per 10 mm filterlength. With respect to the cigarettes, no marked decreases of theflavor components of leaf tobacco and the fragrance of the secondaryflavorant during the storage were observed. However, when each of thecigarettes was smoked, a mild flavor smoking taste peculiar tocigarettes with a charcoal filter could be enjoyed.

Example 6

(A)

A glass tube was charged with 20 mg of the adsorbent obtained inExample 1. At 25° C., vaporized linalool, saturated steam and gaseousnitrogen were simultaneously passed through the interior of the glasstube at respective flow rates of 240 cc/min, 480 cc/min and 80 cc/minfor four hours. Thereafter, the amount of linalool adsorbed on theadsorbent was determined.

The same quantitative determination of linalool was carried out usingthe palm husk activated carbon (Comparative Example) used in theproduction of the adsorbent of Example 1 in place of the adsorbentobtained in Example 1.

(B)

A glass tube was charged with 20 mg of the adsorbent obtained inExample 1. At 25° C., saturated steam was passed through the interior ofthe glass tube for 0.5 hour in order to ensure the exertion of theadsorptive function of the adsorbent. Thereafter, in the same manner asin (A) above, linalool, saturated steam and gaseous nitrogen were passedthrough the interior of the glass tube, and the amount of linalooladsorbed on the adsorbent was determined.

The results are shown in FIG. 5. As is apparent from the results shownin FIG. 5, while the adsorbent of the present invention adsorbed onlyabout 10% of the amount of linalool adsorbed on conventional activatedcarbon under the condition in which the glucan film is not dissolved((A) above), the adsorbent of the present invention adsorbed about 90%of the amount of linalool adsorbed on conventional activated carbonunder the condition in which the glucan film is dissolved ((B) above).

Example 7

Adsorbent-containing cellulose acetate filters were produced using 48 mgof the adsorbent of the present invention obtained in Example 1 and 40mg of the conventional palm husk activated carbon used in Example 1,respectively, in accordance with the routine procedure for production ofcharcoal filters. The amount of activated carbon contained in 48 mg ofthe adsorbent of the present invention and 40 mg of the palm huskactivated carbon are the same in the amount of activated carbon.

A filter-tipped cigarette shown in FIG. 3 was produced using each of theobtained filters. Menthol was added to each of these filter-tippedcigarettes in an amount of 1.3% by weight based on the amount of tobaccoshreds.

The obtained filter-tipped cigarettes were stored in an atmosphereconditioned at 22° C. and a relative humidity of 60%. Each of thecigarettes was smoked by an automatic smoker one day after, seven daysafter, 20 days after and 57 days after the initiation of the storage,and the amount of menthol contained in mainstream smoke was determinedby the routine procedure. The results are shown in FIG. 6. In FIG. 6,the line a indicates the results with respect to the filter-tippedcigarette containing the adsorbent of the present invention, and theline b the results with respect to the filter-tipped cigarettecontaining the conventional palm husk activated carbon.

It is apparent from the results shown in FIG. 6 that the filter-tippedcigarette containing the adsorbent of the present invention exhibits anincrease of about 46% 7 days after the initiation of the storage, anincrease of about 48% 20 days after the initiation of the storage and anincrease of about 46% 57 days after the initiation of the storage in theamount of menthol contained in mainstream smoke over those of thefilter-tipped cigarette containing the conventional activated carbon.

1. A cigarette filter comprising a cigarette mainstream smoke componentadsorbent comprising particulate activated carbon and a water-solubleglucan film supported by the particulate activated carbon.
 2. Thecigarette filter according to claim 1, wherein the glucan film is formedof pullulan.
 3. The cigarette filter according to claim 1, wherein theglucan film contains a colorant other than black colorants.
 4. Thecigarette filter according to claim 1, wherein the glucan film is freeof flavorants.